It is well known in the prior art to provide an instrument cluster assembly that provides information to the driver regarding speed, fuel level, and an unlimited variety of other information. Depending on the desired design effect, it is commonly known to provide this information in either a traditional analogue form, including gauges having dials with pointers, or alternately in a form having a digital appearance. Most conventional analogue instrument cluster displays include gages that are backlit with an array of incandescent bulbs or acrylic light pipes that are placed behind the cluster. These bulbs require a certain amount of air for cooling, thus driving a certain space requirement or volume requirement for packaging the incandescent bulbs in the instrument cluster panel. With the incandescent bulbs, it is difficult to completely eliminate bright spots and to get an even illumination of the instrument cluster graphics. Typically, the pointers used in analogue clusters are made of relatively costly, clear, acrylic light pipes which project light along the length of the pointers. Thus, a small amount of light can leak beneath the pointer and cause a glow beneath the pointers. In addition, the pointers are limited in shape and size since they must be wide enough to accommodate the light pipe, thus dictating the use of relatively straight pointers with relatively wide tips. Furthermore, the pointers are limited in color, based on the optical limitations of the transparency of the light pipes. Light pipes also have the limitation of requiring the graphics to remain on one plane.
Another method of lighting an analogue instrument cluster is to front-flood the instrument cluster with visible light provided by a plurality of incandescent or fluorescent bulbs placed above and below the instrument cluster. The front-flood method has the limitations of requiring a large amount of bulbs and a relatively large packaging space. In addition, the front-flooding of the instrument cluster by visible light illuminates the entire cluster, not just the informational features, giving a less attractive appearance than the backlit version.
Furthermore, instrument clusters of the prior art have many separate components that must be assembled directly to the instrument panel at the vehicle assembly location. This assembly process can be cumbersome.
As vehicle manufacturers progress in vehicle designs, new and innovative looks are desirable for the vehicle interior. In the area of instrumentation, design goals include providing economical instrumentation that is easy to read, less bulky, less heavy, easy to assembly to the vehicle, and more flexible in design. Obtaining some or all of these goals opens the opportunity for more aesthetically pleasing designs of instrument cluster displays.